In the case of driving a vehicle, users frequently park the vehicle in a predetermined parking space. In the case of parking the vehicle, since backward travel is frequently performed, many users feel difficulty in parking the vehicle. Further, regardless of users feeling difficulty in parking the vehicle, since the visibility at the rear of the vehicle is poor as compared with the visibility in front of the vehicle, users feel some stress in backward travel as compared with forward travel. In this regard, there has been used a technique of allowing users to easily park a vehicle in a target parking space when parking the vehicle, or a technique of displaying an expected travel locus of a vehicle as well as the situations at the rear of the vehicle when reversing the vehicle. A technique described in JP3374833B has been proposed as one example of such a technique.
A vehicle-reversing assist apparatus described in JP3374833B has a function of performing a steering assist guide display to allow a driver to understand a steering timing, a steering amount and a distance in which a vehicle travels backward when the driver parks the vehicle. The vehicle-reversing assist apparatus includes a camera for capturing a view of the rear of the vehicle, a turning start recognition means for detecting the start of a turning operation of the vehicle, and a turning angle detection means for detecting a turning angle after the turning operation is started. The vehicle-reversing assist apparatus having such a configuration superimposes and displays a guide display line based on the turning angle on an image (hereinafter, referred to as “camera image”) captured by the camera when the vehicle is reversed.
In the vehicle-reversing assist apparatus described in JP3374833B, it is preferred to superimpose and display a guide line (one example of an index line) for allowing a driver to understand the position relationship between an obstacle reflected in the camera image and a vehicle. However, due to the superimposition of the guide line, the visibility of the camera image may be obstructed. When an obstacle or a target position, in which the vehicle is to be parked, is sufficiently spaced apart from the vehicle, it is preferred to enhance the visibility of the whole of the camera image for the jumping out of hurried pedestrians. Further, a case may occur in which the driver does not notice the whole of the camera image by paying attention only to the vicinity of the superimposed guide line.
A need exists for a driving assist apparatus which is not susceptible to the drawback mentioned above.